Hi Bruno:

For dinner/cocktail background music, you can play things, like Ipanema, Misty, Wave, CLose to you, A walk to the Black Forest, How insensitive, some waltzes, Spanish Eyes, It had to be you, Something Stupid, Where is the love, L.O.V.E., Secret Love, etc..Some of the nice show tunes, nothing to LOUD or to much Rhythm, people has the trend to keep the beat, and if they are eating, you want to keep the dynamics, medium, Slow, Medium fast, etc.....go for a Medium Foxtrot(110-130s), Ballad or Waltz(90-109), Fast Fox (140-150s), Rhumba 105, Ipanema 130s, Memory (Cats) 70s, All of me 130s, Yesterday 80s, Poor people of Paris, keep variety of tempos, 40s to 80s, from Sinatra, Beatles, BeeGees, Willie Nelson, Jobim, Neil Diamond, Miller, Basie, Steve Wonder, Straisand, Dion, Kenny Rogers, Lionel Ritchie, etc....
If is a dinner event, I stay away from Polkas, Rock, Boggies, Sambas (Unless the slow type around 100 or less BPM, could play CUando Cuando, Orpheus Samba), you can be rhythmic but in the soft side, so pick styles that do not have to much BOOM BOOM.

I recommend to "Shuffle" tempos, never play 2 or 3 songs at the same tempo (unless is a VERY short medley), if is to long, it becomes lethargic, Change Keys, never play 2-3 songs in the same key, if you have to, use the transpose button, so, keep changing tempos, music eras, shuffle, American Standards, Latin, Country, Waltzes, Pop, Show Tunes etc.
Hope this helps.

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mdorantes